What is the maximum RAM I can have in my laptop?

I have a Macbook 13inch Mid 2009 I believe according to Mac tracker, I currently have 3GB 800MHz DDR2 SDRAM installed from when I purchased it, Is this the max ram for my macbook or can I install more? I mainly do alot of photoshop work so more ram would be handy.

Mac Specs : 2.13GHz Intel Core 2 Duo & 3GB 800MHz DDR2 SDRAM


Thanks in advance

Intell said:

That Macbook can take a maximum of 6GB in the form of one 2GB stick and one 4GB stick.

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Thank you for your reply Just what I looking for

Would these work in my macbook?

http://www.amazon.co.uk/Komputerbay-MACMEMORY-single-PC2-6300-Macbook/dp/B00I3JOX9O

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http://www.amazon.co.uk/Komputerbay-MACMEMORY-single-PC2-6300-Macbook/dp/B00I3JOX9O

Intell said:

You posted two identical links to a 4GB stick. Yes it will work, but you need one of those and one 2GB stick for the maximum of 6GB. Two 4GB sticks will not work.

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The 2GB is on the drop down link on which RAM to select on that page, Thought they were different links Thanks for the advice and help much appreciated